Jim McKelvey on Jack Dorsey

Jack joined one of my companies – we did publishing software for conferences – when he was 15, basically as an intern. He was still at school and worked for us for three summers. His mother owned a coffee shop. This was before you could get Ritalin readily, so we used to use the chocolate-covered espresso beans to stay awake during long hauls. One of my co-workers got talking to her. She mentioned that her son liked working with computers, so we agreed for him to come in for an interview, then forgot about it.

He showed up in the middle of a horrendous deadline, and introduced himself to me. I said, "Oh, hi, I'll be with you in a minute", and I turned back to the computer and promptly forgot he was there. I probably worked for half an hour until I turned around and he hadn't moved. I was like, "Oh my God, sorry." I asked if he could work a scanner and he said yes, so we sat him in front of a scanner and he pulled an all-nighter that first day.

He was smart, did as he was told; he had a very good manner. My nickname for him was Jack the Genius. You would give him a task and he would be able to do it.

We got along great. That's probably why he later asked me to join his new company [Square, a mobile payments company] when he was out of Twitter and looking for something to do. That second time we worked together, we were partners.

During his second year working for me, I hired some other guys to work under him. One was in his 30s, and Jack was 16. Did I think he'd go on to great things? Oh yeah.